st: updated version of -xml_tab- is available from SSC

Thanks you Kit Baum, updated version of -xml_tab- is available from SSC
archives.

To install the updates, type. ssc install xml_tab, replace; or
use -adoupdate-command.

Changes in this version include:
New -newappend- option, that simplifies the use of -xml_tab- in loops;
In the -format- option, formatting codes now can contain letters (or
any combination of letters and numbers), hopefully making it more intuitive:

for example n2310 means numeric cell, that is centered vertically
(2), right adjusted (3), bold face font (1) and 0 digits after the decimal.
same format can be written as n2310, ncrb0, NCRB0, N2rB0 etc.

For those who might not be familiar with -xml_tab- it's a program that saves
Stata output into XML file that can be directly opened in MS
Excel or OpenOffice Calc. The program is quite flexible to essentially do
everything Excel or Calc can do in terms of formatting of a table, but from
within Stata. The unique feature of -xml_tab- is that the program allows
controlling the formatting of the output tables. -xml_tab- can output the
results using different fonts, change borders of the output cells, insert
rows and columns, etc.

One can combine multiple estimation results saved using -estimates store-
and output results next to each other in a single table. Using Excel's
workbook format allows saving tables on different sheets of the same XML
file (workbook). This feature can be useful when there's a big number of
output tables generated using loops that need to be collected into a single
file.

We would be thankful for any suggestions about the additional options and
improvements in -xml_tab-.